Signal lock is only an issue with digital signals - it is related to the processor having to identify which type (format) of digital signal is being received, be it PCM (such as CD's), DTS, DTS ES, Dolby 5.1, or Dolby _._ (since Dolby can include any number of channels less than 5.1). With an analog signal, the issue is moot because there's only one option to choose from.